[tex]\displaystyle\bf\\2)\\\\25a-ab^{2} =a\cdot\Big(25-b^{2} \Big)=a\cdot\Big(5^{2} -b^{2} \Big)=a\cdot\Big(5-b\Big)\cdot\Big((5+b\Big)\\\\\\2)\\\\0,5\Big(x-4\Big)+3x=5\\\\0,5x-2+3x=5\\\\3,5x=5+2\\\\3,5x=7\\\\x=7:3,5=2\\\\\boxed{x=2}[/tex]

Ответ:

Объяснение:

2. 25а-а[tex]b^{2}[/tex]=a(25-[tex]b^{2}[/tex])=a([tex]5^{2}[/tex]-[tex]b^{2}[/tex])=a(5-b)(5+b)

3. 0.5(x-4)+3x=5

0.5x-2+3x=5

0.5x+3x=5+2

3.5x=7

x=2